1. Field of the Invention
The present invention relates generally to a novel fiber optic sensor device, and a method of manufacture therefor.
2. Description of the Prior Art
The following patents, U.S. Pat. Nos. 4,297,887 to Bucaro, 4,363,114 to Bucaro et al., and 4,442,350 to Rashleigh each generally disclose the use of fiber optics in a sensor.
It is known that the theoretical responsivity of fiber optic sensors increases linearly with fiber length, and that fiber strip metallic glass magnetostrictive sensors have severe limitations for use with large fiber length. This trade-off has led to fiber optic sensors having cylinders of a metallic glass magnetostrictive material formed by epoxying a number of layers of metallic glass ribbon together into a cylindrical form. An optical fiber is then wrapped around the cylinder and epoxied in place. Because the optical fiber must be wrapped around the metallic glass cylinder under tension so that the strain generated in the metallic glass ribbon can be transferred from the magnetostrictive material to the fiber, at least four layers of metallic glass must be used to form the cylinder strong enough to support the fiber winding process.
The use of multiple layers of metallic glass generates demagnetization effects and reduces the strain transfer efficiency between the optical fiber and the metallic glass sensing material.
The deleterious effects of demagnetization and inefficient strain transfer due to multiple layers of metallic glass are alleviated by Applicants' novel invention.